Barış ERDEM (030060085) 3rd Week

Plasma arc cutting

                The plasma arc cutting process severs metal bymeans highly concentrated arc jet that has sufficient energy and force not only to melt the metal, but also to eject the molten metal. Because melting rather than oxidation is the predominant cutting mode plasma arc cutting can be used to cut any metal. 

                It is important to bear in mind that plasma arc cutting is a fundamentally different process from oxyfuel cutting, retying primarily on the heat generated by an electric arc to melt and sever the parent material. Consequently, additional safety hazards exits from operator should understand these hazards and take appropriate precautions. Appropriate safety information is referenced in AWS C5.2-83 “Recommended Practices For Plasma Arc Cutting.”
(Transportation Research Board, National Research Council, NCHRP Report 384, Plasma Arc Cutting of Bridge Steels, p.80)

Cold Welding

                According to American Welding Society (AWS), “Cold welding(CW) is a solid-stade process in which pressure is used at room temperature to produce coalescence of metals with substantial plastic deformation at the weld.” Cold welding processes are characterized by a notable absence of heat, whether appied from an external source or generated internal to the process itself.

                Cold welding is ideally suited to the joining of dissimilar metals since no intermixing of base metals is required or obtained. This allows inherent chemical incompatibilities that would prevent or make fusion welding difficult to be overcome. The best example is the cold welding of relatively pure aliminum to relatively pure copper to produce electrical connections.

(Messler R. W., Principles of Welding, 2004, p.98)

Forge Welding

                According to AWS, “Forge welding (FOW) is a solid-state welding process that produces a weld by heating workpieces to welding (hot working) temperatures and applying blows sufficient to cause deformation at the faying surfaces.” Without question, forge welding was the earliest form of welding, and still used today by blacksmiths, among others. The well-known and highly regarded Damascus steel swords made by ancient Syrians are an excelent example of ancient forge welding, while hand-forged chains and wrought-iron products are good examples of modern forge welding by blacksmiths.

(Messler R.W., Principles of Welding, 2004, p.101)

Explosive Welding

                Explosive welding is a process based on the controlled application of enormous power generated by detonating explosives. The surfaces of the parts to be joined must be clean without contamination of oxides etc. These clean surfaces are pressed at pressure of the order of million kg/sqcm generated by the explosive. Combination of dissimilar metals-aliminium to steel or titanium to steel – can be readily obtained by this process.

(Radhakrishnan V. M., Welding Technology and Design, Second Edition, 2005, p.38)